[Enhancement]: Replace texture atlas with individual PNGs and convert item IDs to item namespaces

[LandonAndEmma]

Terrain.png is a texture atlas for every block in the game, it has existed since the very first version in Minecraft but because of this it's cumbersome to replace, add, or remove textures however even thought it was removed from Java edition in 2013 4J never replaced it with the modern system.
https://minecraft.wiki/index.php?title=Terrain.png

In 1.13 Minecraft switched from item IDs to item namespaces which helped in development of never blocks and features because developers did not have to remember each ID they could just read it.

[LandonAndEmma]

Since IDs will be replaced with namespaces and worlds use block IDs instead of namespaces that could break worlds from loading, so you’d need a function that holds every ID in the latest legacy console edition (1.14) PS4 edition and their modern Minecraft namespaces, however since we aren’t even remotely close to those updates those could default to null blocks so this could also add loading functionality for later versions of world files and also easily updatable.

The textures atlas since texture packs use the same function and format we’ll need a helper function to load texture packs textures like how the OG does while also including the new version with no texture atlas.